\documentclass[UTF8]{ctexart}
    \usepackage{ctex}
    \author{宋昊天}
    \date{\today}
    \title{report}
\begin{document}
\maketitle

\section{section 1}
$\beta$为初始参量
a positive exponent which represents the e"ciency of
the acceleration
选取1或2进行计算 第一次选取2

\subsection{another sebsection}git
\subsection{Math formula}
the sample of power: $x^2$
\\other samples: $x^123$

$$x^{x^3+y^{89}}$$
\\ the sample of subscript:
$$x_123$$ $$x_{123}$$

$$x_\alpha$$

square$$\sqrt{x_1}$$
$$\sqrt[5]{x}$$
\section{formula number}
\begin{equation}
          X(k)=\sum_(i=1)^100 x(n)
\end{equation}

footnote\footnote{This is a footnote}\underline{underline}
% TODO
\tableofcontents
\section{introduction to LaTex}
\ldots and here it ends
\end{document}
